According to Dr. Greg Hager, professor of computer science at Johns Hopkins University, “In 1960 in Japan they figured out that the average Japanese man, when he walked 10,000 steps a day burned something like 3,000 calories and that is what they thought the average person should consume so they picked 10,000 steps as a number”.

According to Hager, asking everyone to shoot for 10,000 steps each day could be harmful to the elderly or those with medical conditions that make it unwise for them to jump into that level of exercise, even if it's walking. He also noted that those with shorter legs have an easier time hitting the 10,000 step goal because they have to take more steps than longer-legged people to cover the distance. The bottom line is that 10,000 steps may be too many for some and too few for others.

A more recent study found that women who took 4,400 steps per day were about 40% less likely to die during a follow-up period of just over four years, compared to women who took 2,7000 steps. Interestingly, women in the study who walked more than 7,500 steps each day got no extra boost in longevity. The study was published in JAMA Internal Medicine.